JP2012013520A - Optical tomographic imaging device and method for estimating pressing force of its optical probe - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical tomographic imaging device capable of checking pressing force of an optical probe to a measuring object using an existing optical probe, and to provide a method for estimating the pressing force of the optical probe.SOLUTION: A contact area detection part 484 detects a contact area of an optical probe 500 in contact with the measuring object S by an interference signal. A pressing force estimation part 490 obtains the size of a contact range based on information on the contact area detected by the contact area detection part 484, and then determines whether or not the size of the obtained contact range is within a preset appropriate range to estimate suitability of the pressing force of the optical probe 500 to the measuring object S.

Description

  The present invention relates to an optical tomographic imaging apparatus and an optical probe pressing force estimation method, and more particularly to an optical tomographic imaging apparatus for irradiating a measurement target with light and acquiring an optical tomographic image of the measurement target from the reflected light. And an optical probe pressing force estimation method.

  As a method for acquiring a cross-sectional image without cutting a measurement target such as a living tissue, an optical tomographic imaging apparatus using OCT (Optical Coherence Tomography) measurement is known (for example, Patent Document 1). In this optical tomographic imaging apparatus, an optical probe is inserted into a body cavity such as a blood vessel, bile duct, pancreatic duct, stomach, esophagus, large intestine, and the like, and an optical tomographic image to be measured is acquired by performing radial scanning. The measurement is performed by pressing the optical probe against the body cavity wall. This is to increase the depth of measurement and to suppress body movement of the living body, but if this pressing is excessive, there is a problem that the optical probe is damaged.

  Therefore, Patent Document 2 describes a technique of installing a pressure sensor at the tip of the ultrasonic sensor, quantifying the amount of pressing force on the body cavity wall and displaying it on the monitor, and a technique of warning when excessive pressing is performed. Yes.

JP 2009-72280 A JP-A-6-70930

  However, if a pressure sensor is provided at the tip of the optical probe, there are disadvantages that the number of parts increases, the configuration of the tip is complicated, and the arrangement of the tip is also limited. In addition, the ultrafine optical probe has a problem that it is difficult to provide a pressure sensor.

  The present invention has been made in view of such circumstances, and an optical tomographic imaging apparatus capable of confirming the pressing force of an optical probe on a measurement target using an existing optical probe, and the optical probe pressing An object is to provide a force estimation method.

  In order to achieve the object, the invention according to claim 1 includes a light source, branching means for branching the light emitted from the light source into measurement light and reference light, and a measurement unit in the sheath, The optical probe that irradiates the measurement light from the unit toward the measurement target and acquires the reflected light, driving means for rotating the measurement unit of the optical probe, and the reflected light acquired by the measurement unit of the optical probe And a reference means for generating interference light, interference light detection means for detecting the interference light as an interference signal, and an optical tomographic image from the interference signal detected by the interference light detection means Based on the size of the contact area detected by the contact area detection means, the contact area detection means for detecting the contact area of the optical probe with respect to the measurement object, and the measurement pair. Optical tomographic imaging, comprising: a pressing force estimating means for estimating the pressing force of the optical probe against the pressure; and a notifying means for notifying the pressing force of the optical probe estimated by the pressing force estimating means. Providing equipment.

  In the present invention, the contact area of the optical probe with respect to the measurement target is detected, and the pressing force of the optical probe with respect to the measurement target is estimated based on the size. That is, as the pressing force increases, the contact area also increases, so the pressing force is estimated based on the size of the contact area. Thus, the pressing force can be confirmed without providing a pressure sensor or the like at the tip of the optical probe.

  In the invention according to claim 2, in order to achieve the object, the pressing force estimation means determines whether or not the contact area detected by the contact area detection means is within a preset appropriate range. The optical tomographic imaging apparatus according to claim 1, wherein a pressing force of the optical probe against the measurement object is estimated.

  In this invention, it determines whether the calculated | required contact area | region is in the preset appropriate range, and estimates pressing force. That is, if the obtained contact area is within an appropriate range, it is estimated that the pressing force is appropriate. On the other hand, if the obtained contact area is below the appropriate range, it is estimated that the pressing force is insufficient, and if it exceeds the estimated range, it is estimated that the pressing is excessive.

  The invention according to claim 3 provides the optical tomographic imaging apparatus according to claim 2, wherein the appropriate range is set for each measurement object in order to achieve the object.

  According to the present invention, an appropriate range is set for each measurement target. Even if the hard tissue and the soft tissue are pressed with the same pressing force, the region in contact with the optical probe changes. Therefore, the pressing force can be estimated more accurately by setting an appropriate range for each measurement target.

  In order to achieve the above object, the invention according to claim 4 includes storage means in which a table representing a relationship between the contact area and the pressing force is recorded, and the pressing force estimation means refers to the table, The optical tomographic imaging apparatus according to claim 1, wherein a pressing force of the optical probe with respect to the measurement target is estimated.

  In the present invention, the pressing force is estimated with reference to a table representing the relationship between the contact area and the pressing force prepared in advance. That is, since the contact area changes depending on the pressing force, the relationship between the contact area and the pressing force is obtained in advance, and the relationship is recorded in the table, so that the pressing force can be applied from the contact area only by referring to the table. Can be sought.

  In the invention according to claim 5, in order to achieve the object, the table is prepared for each measurement object and recorded in the storage means, and the pressing force estimation means refers to a table corresponding to the measurement object. The optical tomographic imaging apparatus according to claim 4, wherein a pressing force of the optical probe against the measurement object is estimated.

  According to the present invention, a table is prepared for each measurement target and recorded in the storage unit. Thereby, the pressing force can be estimated more accurately.

  In order to achieve the above object, the invention according to claim 6 includes a light source, branching means for branching light emitted from the light source into measurement light and reference light, and a measurement unit in the sheath, The optical probe that irradiates the measurement light from the unit toward the measurement target and acquires the reflected light, driving means for rotating the measurement unit of the optical probe, and the reflected light acquired by the measurement unit of the optical probe And a reference means for generating interference light, interference light detection means for detecting the interference light as an interference signal, and an optical tomographic image from the interference signal detected by the interference light detection means Based on the optical tomographic image acquired by the optical tomographic image acquisition means and the optical tomographic image acquired by the optical tomographic image acquisition means, and based on the shape of the surface, Light pro An optical tomographic imaging apparatus comprising: a pressing force estimation unit that estimates a pressing force of a hub; and a notification unit that notifies the pressing force of the optical probe estimated by the pressing force estimation unit. To do.

  In the present invention, the surface shape of the measurement target is detected from the optical tomographic image, and the pressing force of the optical probe on the measurement target is estimated based on the detected surface shape. That is, since the surface shape of the measurement target changes due to the pressing force, the surface shape of the measurement target when the optical probe is pressed is obtained to estimate the pressing force. Thus, the pressing force can be confirmed without providing a pressure sensor or the like at the tip of the optical probe.

  In the invention according to claim 7, in order to achieve the object, the pressing force estimation means extracts a curve that delineates the surface of the measurement object, and evaluates an integral value of an absolute value of a differential coefficient of the curve as an evaluation value. The optical tomographic imaging apparatus according to claim 6, wherein the optical tomographic imaging apparatus according to claim 6, wherein the pressing force of the optical probe with respect to the measurement target is estimated based on the evaluation value.

  In the present invention, a curve demarcating the surface of the measurement target (curve representing the surface shape of the measurement target) is extracted, an integral value of the absolute value of the differential coefficient of the curve is obtained as an evaluation value, and based on the obtained evaluation value Estimate the pressing force. In general, the surface shape of the measurement object is greatly deformed as the pressing force of the optical probe is increased (the amount of wrapping around the outer periphery of the optical probe is increased). Since the integral value of the absolute value of the derivative of the curve is an index indicating the degree of deformation of the curve, the degree of deformation of the curve can be known by obtaining the integral value of the absolute value of the derivative of the curve. . Therefore, by determining the integral value of the absolute value of the differential coefficient of the curve defining the surface of the measurement object, the pressing force can be estimated based on the magnitude.

  In the invention according to claim 8, in order to achieve the object, the pressing force estimation means determines whether or not the evaluation value is within an appropriate range set in advance, and The optical tomographic imaging apparatus according to claim 7, wherein the pressing force of the optical probe is estimated.

  In the present invention, it is determined whether or not the obtained evaluation value is within an appropriate range set in advance, and the pressing force is estimated. That is, if the obtained evaluation value is within an appropriate range, it is estimated that the pressing force is appropriate. On the other hand, if the obtained evaluation value is below the appropriate range, it is estimated that the pressing force is insufficient, and if it exceeds the estimated value, it is estimated that the pressing is excessive.

  The invention according to claim 9 provides the optical tomographic imaging apparatus according to claim 8, wherein the appropriate range is set for each measurement object in order to achieve the object.

  According to the present invention, an appropriate range is set for each measurement target. Even if the hard tissue and the soft tissue are pressed with the same pressing force, the region in contact with the optical probe changes. Therefore, the pressing force can be estimated more accurately by setting an appropriate range for each measurement target.

  In the invention according to claim 10, in order to achieve the object, the pressing force estimation unit refers to a table representing a relationship between the pressing force of the optical probe with respect to the measurement target and the evaluation value, and The optical tomographic imaging apparatus according to claim 7, wherein a pressing force of the optical probe against a measurement target is estimated.

  In the present invention, the pressing force is estimated with reference to a table representing the relationship between the evaluation value prepared in advance and the pressing force. In other words, since the evaluation value varies depending on the pressing force, the relationship between the evaluation value and the pressing force is obtained in advance, and the relationship is recorded in the table, so that the pressing force can be calculated from the evaluation value only by referring to the table. Can be sought.

  The invention according to claim 11 provides the optical tomographic imaging apparatus according to claim 10, wherein the table is prepared for each measurement object in order to achieve the object.

  According to the present invention, a table is prepared for each measurement target and recorded in the storage unit. Thereby, the pressing force can be estimated more accurately.

  In order to achieve the object, the invention according to claim 12 includes a display unit, and the notification unit estimates the pressing force estimation unit together with the optical tomographic image acquired by the optical tomographic image acquisition unit. The optical tomographic imaging apparatus according to any one of claims 1 to 11, wherein the pressing force of the optical probe is displayed on the display means to notify the pressing force of the optical probe.

  According to the present invention, the obtained information of the pressing force of the optical probe is displayed on the display means together with the optical tomographic image and notified. Thereby, the pressing force can be confirmed on the same screen as the screen on which the optical tomographic image is displayed.

  The invention according to claim 13 determines whether or not the pressing force of the optical probe with respect to the measurement target is appropriate based on the pressing force of the optical probe estimated by the pressing force estimation means in order to achieve the object. The apparatus according to claim 1, further comprising: a warning means that warns when the determination means determines that the pressing force of the optical probe is not appropriate. An optical tomographic imaging apparatus is provided.

  According to the present invention, whether or not the pressing force is appropriate is determined, and a warning is given if the pressing force is not appropriate. Thereby, damage of the optical probe due to excessive pressing or the like can be prevented.

  In order to achieve the object, the invention according to claim 14 includes a light source, branching means for branching the light emitted from the light source into measurement light and reference light, and a measurement unit in the sheath, The optical probe that irradiates the measurement light from the unit toward the measurement target and acquires the reflected light, driving means for rotating the measurement unit of the optical probe, and the reflected light acquired by the measurement unit of the optical probe And a reference means for generating interference light, interference light detection means for detecting the interference light as an interference signal, and an optical tomographic image from the interference signal detected by the interference light detection means An optical tomography pressing force estimation method for an optical tomographic imaging apparatus comprising: an optical tomographic image acquisition means for detecting a contact area of the optical probe with respect to the measurement object, and based on the size of the contact area The measurement To provide an optical probe pressing force estimating method of the optical tomographic imaging apparatus and estimates the pressing force of the optical probe to the target.

  According to the present invention, the contact area of the optical probe with respect to the measurement object is detected, and the pressing force of the optical probe with respect to the measurement object is estimated based on the size of the contact area. That is, the pressing force of the optical probe is estimated based on the degree of contact.

  In order to achieve the above object, the invention according to claim 15 includes a light source, branching means for branching light emitted from the light source into measurement light and reference light, and a measurement unit in the sheath, The optical probe that irradiates the measurement light from the unit toward the measurement target and acquires the reflected light, driving means for rotating the measurement unit of the optical probe, and the reflected light acquired by the measurement unit of the optical probe And a reference means for generating interference light, interference light detection means for detecting the interference light as an interference signal, and an optical tomographic image from the interference signal detected by the interference light detection means An optical probe pressing force estimation method for an optical tomographic imaging apparatus comprising: an optical tomographic image acquisition means for detecting a shape of a surface of the measurement target based on the optical tomographic image; Based on the shape, To provide an optical probe pressing force estimating method of the optical tomographic imaging apparatus and estimates the pressing force of the optical probe to the target.

  According to the present invention, the pressing force of the optical probe on the measurement target is estimated based on the shape of the surface of the measurement target. That is, the pressing force of the optical probe is estimated based on the degree of deformation of the surface of the measurement target.

  According to the present invention, it is possible to confirm the pressing force of an optical probe on a measurement target using an existing optical probe.

External view of diagnostic imaging device composed of optical tomographic imaging device and endoscope device Block diagram showing the configuration of an optical tomographic imaging apparatus Side sectional view showing the configuration of the tip of the probe insertion section The block diagram which shows the structure of the process part with which the OCT processor was equipped. Explanatory drawing for demonstrating the information of the measurement position of the rotation direction of an optical probe A graph showing a schematic example of a calculation result obtained by performing FFT on an interference signal Explanatory drawing for demonstrating the detection method of a contact area The figure which shows a mode that an optical tomographic image is acquired using an optical probe Flow chart showing the procedure for detecting the position of the outer periphery of the optical probe based on the interference signal Flow chart showing the procedure for detecting the contact area between the sheath and the measurement object Flowchart showing image processing procedure for creating optical tomographic image Flow chart showing the procedure for estimating the pressing force of the optical probe based on the information of the contact area with the measurement object The figure which shows an example of the screen displayed on a monitor apparatus The figure which shows another example of the screen displayed on a monitor apparatus A diagram schematically showing the surface shape of the measurement target when the optical probe is pressed The block diagram which shows the structure of other embodiment of the process part of an optical tomographic imaging apparatus. Flow chart showing the procedure for estimating the pressing force from an optical tomographic image

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

≪Diagnostic imaging device≫
FIG. 1 is an external view of an image diagnostic apparatus including an optical tomographic imaging apparatus and an endoscope apparatus.

  As shown in the figure, the diagnostic imaging apparatus 10 includes an endoscope apparatus 12, an optical tomographic imaging apparatus 14, and a monitor apparatus 16. The endoscope apparatus 12 is an electronic endoscope apparatus that converts an optical image of a subject into an electric signal and outputs the electric signal. The endoscope apparatus 12 includes an endoscope 100, an endoscope processor 200, and a light source device 300. On the other hand, the optical tomographic imaging apparatus 14 includes an OCT processor 400 and an optical probe 500. The diagnostic imaging apparatus 10 displays an image (observation image) acquired by the endoscope apparatus 12 on the monitor apparatus 16 and also displays an image (optical tomographic image) acquired by the optical tomographic imaging apparatus 14 on the monitor apparatus 16. indicate.

  Although not shown in FIG. 1, the diagnostic imaging apparatus 10 is further provided with an input device (keyboard, mouse, etc.) for performing a predetermined operation, information input, and the like.

<Endoscope device>
The endoscope apparatus 12 includes an endoscope 100, an endoscope processor 200, and a light source device 300.

[Endoscope]
The endoscope 100 includes a hand operation unit 112 and an endoscope insertion unit 114, and is connected to the endoscope processor 200 and the light source device 300 via a universal cable 116.

  The hand operation unit 112 is provided with various operation buttons such as an air / water supply button 130, an angle knob 132, a suction button 134, and a shutter button 136. The surgeon operates these operation buttons to perform a required operation.

  In addition, the hand operation unit 112 is provided with a forceps insertion port 138 communicated with a forceps port 156 provided at the distal end of the endoscope insertion unit 114. By using the forceps insertion port 138, an optical tomography is provided. The optical probe 500 of the imaging device 14 is inserted into the body cavity of the subject.

  The endoscope insertion portion 114 includes a flexible flexible portion 140, a bending portion 142 that is bent by an angle knob of the hand operation portion 112, and a distal end portion 144. The endoscope insertion portion 114 is inserted into the body of the subject.

  An observation optical system 150, a pair of illumination optical systems 152, a cleaning nozzle 154, and a forceps port 156 are provided on the end surface of the distal end portion 144. The observation optical system 150 forms an optical image of a subject on a light receiving surface of a solid-state imaging device (for example, a CCD) (not shown). The solid-state image sensor converts an optical image of a subject formed on the light receiving surface into an electric signal (image signal) and outputs the electric signal. The illumination optical system 152 irradiates illumination light toward the imaging range of the observation optical system 150. The cleaning nozzle 154 selectively jets water or air toward the observation optical system 150 to clean the observation optical system 150.

[Endoscope processor]
The endoscope processor 200 has a built-in image signal processing circuit (not shown), takes in a CCD image signal from the endoscope 100, and generates image data of an observation image. The generated image data of the observation image is converted into a signal format that can be output to the monitor device 16 and output to the monitor device 16. Thereby, an observation image obtained by the endoscope 100 is displayed on the monitor device 16.

[Light source device]
The light source device 300 incorporates a light source (not shown), and supplies the illumination light emitted from the illumination optical system 152 to the endoscope 100. Light from the light source is emitted to the illumination optical system 152 via a light guide (not shown), and is irradiated toward the subject by the illumination optical system 152.

<Optical tomography system>
FIG. 2 is a block diagram showing a configuration of the optical tomographic imaging apparatus.

  The optical tomographic imaging apparatus 14 includes an OCT processor 400 and an optical probe 500.

[OCT processor]
As shown in FIG. 2, the optical tomographic imaging apparatus 14 mainly branches the light source unit 412 and the light emitted from the light source unit 412 into measurement light and reference light, and reflects light from the measurement target and reference. The branching / multiplexing unit 414 that combines the light to generate interference light, the branching unit 416, the optical path length adjustment unit 418 that adjusts the optical path length of the reference light, and the interference light generated by the branching / combining unit 414 An interference light detection unit 420 that detects an interference signal and a processing unit 422 that processes the interference signal detected by the interference light detection unit 420 are included.

[Light source unit]
The light source unit 412 includes a semiconductor optical amplifier 440, an optical branching unit 442, a collimator lens 444, a diffraction grating element 446, an optical system 448, and a rotating polygon mirror 450, and sweeps the frequency at a constant period. Laser beam La is emitted.

  The semiconductor optical amplifier 440 emits weak emitted light and amplifies incident light when a drive current is applied. The semiconductor optical amplifier 440 is connected with an optical fiber FB10. Specifically, one end of the optical fiber FB10 is connected to a portion where light is emitted from the semiconductor optical amplifier 440, and the other end of the optical fiber FB10 is connected to a portion where light enters the semiconductor optical amplifier 440. . The light emitted from the semiconductor optical amplifier 440 is emitted to the optical fiber FB10 and enters the semiconductor optical amplifier 440 again. Thus, by forming a loop of the optical path between the semiconductor optical amplifier 440 and the optical fiber FB10, the semiconductor optical amplifier 440 and the optical fiber FB10 become optical resonators, and a drive current is applied to the semiconductor optical amplifier 440. A pulsed laser beam is generated.

  The optical branching unit 442 is provided on the optical path of the optical fiber FB10. An optical fiber FB11 is connected to the optical branching unit 442, and a part of light guided in the optical fiber FB10 is branched to the optical fiber FB11.

  The collimator lens 444 is disposed at the other end of the optical fiber FB11, and collimates the light emitted from the optical fiber FB11.

  The diffraction grating element 446 is disposed at a predetermined angle on the optical path of the parallel light generated by the collimator lens 444. The diffraction grating element 446 separates the parallel light emitted from the collimator lens 444.

  The optical system 448 is disposed on the optical path of the light split by the diffraction grating element 446. The optical system 448 is composed of a plurality of lenses, refracts the light split by the diffraction grating element 446, and converts the refracted light into parallel light.

  The rotating polygon mirror 450 is disposed on the optical path of the parallel light generated by the optical system 448 and reflects the parallel light emitted from the optical system 448. The rotating polygon mirror 450 is a columnar rotating body having a regular octagonal cross section that rotates at a constant speed in the direction of the arrow R1 in FIG. 1. By rotating, the angle of each side surface (reflection surface) is the optical axis of the optical system 448. Will vary.

  The light emitted from the optical fiber FB11 passes through the collimator lens 444, the diffraction grating element 446, and the optical system 448, and is reflected by the rotary polygon mirror 450. The reflected light is reflected by the optical system 448, the diffraction grating element 446, and the collimator lens. It passes through 444 and enters the optical fiber FB11.

  Here, as described above, since the angle of the reflecting surface of the rotating polygon mirror 450 changes with respect to the optical axis of the optical system 448, the angle at which the rotating polygon mirror 450 reflects light changes with time. For this reason, only the light in a specific frequency region out of the light dispersed by the diffraction grating element 446 enters the optical fiber FB11 again.

  Here, since the light in a specific frequency range incident on the optical fiber FB11 is determined by the angle between the optical axis of the optical system 448 and the reflection surface of the rotary polygon mirror 450, the frequency range of the light incident on the optical fiber FB11 is It changes depending on the angle between the optical axis of the optical system 448 and the reflecting surface of the rotary polygon mirror 450.

  The light in a specific frequency range that has entered the optical fiber FB11 enters the optical fiber FB10 from the optical branching unit 442, and is combined with the light of the optical fiber FB10. Thereby, the pulsed laser light guided to the optical fiber FB10 becomes laser light in a specific frequency range, and the laser light La in the specific frequency range is emitted to the optical fiber FB1.

  Here, since the rotating polygon mirror 450 rotates at a constant speed in the direction of the arrow R1, the wavelength λ of the light incident on the optical fiber FB11 again changes with a constant period as time passes. As a result, the frequency of the laser light La emitted to the optical fiber FB1 also changes at a constant period with the passage of time.

  The light source unit 412 has such a configuration, and emits the laser light La swept in wavelength toward the optical fiber FB1.

[Branching / Combining Section]
The branching / combining unit 414 is composed of, for example, a 2 × 2 optical fiber coupler. An optical fiber FB1, an optical fiber FB2, an optical fiber FB3, and an optical fiber FB4 are connected to the branching / multiplexing unit 414.

  The branching / combining unit 414 divides the laser beam La incident from the light source unit 412 via the optical fiber FB1 into measurement light L1 and reference light L2. Then, the measurement light L1 is incident on the optical fiber FB2, and the reference light L2 is incident on the optical fiber FB3.

  The branching / combining unit 414 receives the reference light L2 incident from the optical path length adjusting unit 418 via the optical fiber FB3 and the reflected light L3 from the measurement target S incident from the optical probe 500 via the optical fiber FB2. The interference light is generated by multiplexing, and the generated interference light is divided into interference light L4 and interference light L5. Then, the interference light L4 is incident on the optical fiber FB4, and the interference light L5 is incident on the optical fiber FB1.

[Branching part]
The branch portion 416 is provided on the optical path of the optical fiber FB1. An optical fiber FB5 is connected to the branch portion 416, and interference light L5 guided to the optical fiber FB1 is incident on the optical fiber FB5.

[Optical path length adjustment section]
The optical path length adjustment unit 418 includes a first optical lens 464 that converts the light emitted from the optical fiber FB3 into parallel light, a second optical lens 466 that collects the light converted into parallel light by the first optical lens 464, and The reflection mirror 468 that reflects the light collected by the second optical lens 466, the base 470 that supports the second optical lens 466 and the reflection mirror 468, and the base 470 are moved in a direction parallel to the optical axis direction. The optical path length of the reference light L2 is adjusted by changing the distance between the first optical lens 464 and the second optical lens 466.

  The first optical lens 464 converts the reference light L2 emitted from the core of the optical fiber FB3 into parallel light, and condenses the reference light L2 reflected by the reflection mirror 468 on the core of the optical fiber FB3.

  The second optical lens 466 condenses the reference light L2 converted into parallel light by the first optical lens 464 on the reflection mirror 468 and makes the reference light L2 reflected by the reflection mirror 468 parallel. As described above, the first optical lens 464 and the second optical lens 466 form a confocal optical system.

  The reflection mirror 468 is disposed at the focal point of the light collected by the second optical lens 466, and reflects the reference light L2 collected by the second optical lens 466.

  The reference light L <b> 2 emitted from the optical fiber FB <b> 3 becomes parallel light by the first optical lens 464 and is collected on the reflection mirror 468 by the second optical lens 466. Thereafter, the reference light L2 reflected by the reflection mirror 468 becomes parallel light by the second optical lens 466, and is condensed on the core of the optical fiber FB3 by the first optical lens 464.

  The base 470 fixes the second optical lens 466 and the reflection mirror 468. The mirror driving mechanism 472 moves the base 470 in the optical axis direction of the first optical lens 464 (the direction of arrow A in FIG. 1).

  The distance between the first optical lens 464 and the second optical lens 466 can be changed by moving the base 470 in the direction of arrow A with the mirror drive mechanism 472, and the optical path length of the reference light L2 can be adjusted. Can do.

(Interference light detector)
The interference light detection unit 420 is connected to the optical fiber FB4 and the optical fiber FB5, detects the light intensity of the interference light L4 guided by the optical fiber FB4, and interferes with the interference light guided by the optical fiber FB5. The light intensity of L5 is detected, and an interference signal is generated based on the information on the light intensity of the obtained interference lights L4 and L5.

[Processing part]
The processing unit 422 processes the interference signal detected by the interference light detection unit 420 to generate an optical tomographic image.

  In addition, the processing unit 422 processes the interference signal detected by the interference light detection unit 420 to contact the measurement probe S with the contact region of the optical probe 500, more precisely, the sheath of the optical probe 500 (the outer cylinder of the optical probe 500). ) An area where the outer peripheral surface of 552 and the surface of the measuring object S can be considered to be in contact is detected.

  Furthermore, the processing unit 422 detects (estimates) the pressing force on the measurement target S based on the detected information on the contact area.

  The configuration and operation of the processing unit 422 will be described in detail later.

[Optical probe]
As shown in FIG. 1, the optical probe 500 includes a probe insertion unit 502 that is inserted into the body cavity of the subject via the endoscope 100, and a drive unit 504 that drives the optical probe 500, and a cable. It is connected to the OCT processor 400 through 506.

(Insertion section)
FIG. 3 is a side sectional view showing the configuration of the tip of the probe insertion portion.

  As shown in the figure, the probe insertion portion 502 of the optical probe 500 includes a sheath 552, a cap 554, an optical fiber 556, a spring 558, a fixed cylinder 560, and a half ball lens 562.

  The sheath 552 is a flexible cylindrical catheter-like member, and is made of a material that can transmit the measurement light L1 and the reflected light L3 (in this embodiment, a transparent material). The sheath 552 is only required to be transparent only at least at the distal end (the portion where the measurement light L1 and the reflected light L3 pass), and the entire sheath 552 is not necessarily formed transparently.

  The cap 554 is provided at the distal end of the sheath 552 and closes the distal end of the sheath 552.

  The optical fiber 556 is accommodated in the sheath 552 along the sheath 552. When the optical probe 500 is connected to the OCT processor 400, the optical fiber 556 is connected to the optical fiber FB2 of the OCT processor 400. The optical fiber 556 guides the measurement light L1 emitted from the optical fiber FB2 to the half ball lens 562, and guides the reflected light L3 from the measurement target S acquired by the half ball lens 562 to the optical fiber FB2. .

  The spring 558 is disposed on the outer periphery of the optical fiber 556.

  Half ball lens 562 is arranged at the tip of optical fiber 556, and constitutes a measurement part. The half ball lens 562 condenses the measurement light L1 emitted from the optical fiber 556 and emits the measurement light L1 toward the measurement target S, and condenses the reflected light L3 from the measurement target S to obtain the optical fiber 556. Is incident on.

  The fixed cylinder 560 is disposed at the tip of the optical fiber 556 and fixes the half ball lens 562 to the end of the optical fiber 556. The tip of the spring 558 is fixed to the fixed cylinder 560.

〔Drive part〕
The drive unit 504 is connected to the proximal end portion of the probe insertion unit 502, and rotates and moves the optical fiber 556 of the probe insertion unit 502 in the sheath 552 by a built-in drive mechanism (not shown).

  The optical fiber 556 of the probe insertion unit 502 is connected to the optical fiber FB2 in the driving unit 504. At this time, the optical fiber 556 and the optical fiber FB2 are connected via a rotary joint so that the rotation of the optical fiber 556 rotated by the drive mechanism is not transmitted to the FB2.

  Further, the drive unit 504 detects the rotation and movement of the optical fiber 556 to detect the irradiation position of the measurement light L1, that is, the measurement position (measurement position in the rotation direction and measurement position in the axial direction). A position detection sensor (not shown) is provided. The position information of the measurement position detected by the measurement position detection sensor is taken into the processing unit 422 of the OCT processor 400 via the cable 506.

<Details of processing unit configuration>
FIG. 4 is a block diagram illustrating a configuration of a processing unit provided in the OCT processor.

  As shown in the figure, the processing unit 422 includes an interference signal acquisition unit 480, an A / D conversion unit 482, a contact area detection unit 484, an optical tomographic image generation unit 486, a correction unit 488, and a pressing force estimation. Part 490.

[Interference signal acquisition unit]
The interference signal acquisition unit 480 acquires the interference signal detected by the interference light detection unit 420, acquires the position information of the measurement position detected by the measurement position detection sensor (not shown) of the drive unit 504, and performs interference. The signal is associated with the position information of the measurement position.

  FIG. 5 is an explanatory diagram for explaining the information of the measurement position in the rotation direction of the optical probe.

  In the present embodiment, the number of measurements per rotation of the half-ball lens 562 is determined from the rotation speed of the half-ball lens 562 and the cycle of sweeping the frequency of the measurement light L1. As an example, in the present embodiment, it is assumed that the interference signal is acquired 1024 times while the half ball lens 562 rotates once. Note that the rotation of the half ball lens 562 and the acquisition of the interference signal (that is, the cycle of the measurement light L1 sweep) are constant.

  Therefore, as shown in FIG. 5, the position in the rotation direction of the measurement light L1, that is, the measurement position in the rotation direction, moves from the rotation center by a predetermined angle in order from n = 1. Since the position where the interference signal is acquired in this way moves by a predetermined angle, the line number n can be associated with the measurement position of each interference signal. Further, since the half ball lens 562 is rotated, the measurement position of n = 1024 and the measurement position of n = 1 are adjacent to each other.

  The interference signal associated with the position information of the measurement position is output to the A / D conversion unit 482.

[A / D converter]
The interference signal output from the interference light detection unit 420 is an analog signal. The A / D converter 482 converts the interference signal output as the analog signal into a digital signal. The digitally converted interference signal is output to the contact area detection unit 484 and the optical tomographic image generation unit 486.

[Contact area detector]
The contact region detection unit 484 subjects the interference signal converted into a digital signal by the A / D conversion unit 482 to FFT (Fast Fourier Transform), acquires the relationship between the frequency component and the intensity of the interference signal, By associating the depth direction (the direction away from the rotation center), information on the relationship between the depth direction and the strength is acquired. Then, the position of the surface of the sheath 552 (the position of the outer periphery of the optical probe) at the position where the measurement light L1 is transmitted is detected from the acquired information on the relationship between the depth direction and the intensity, and the sheath at the position where the measurement light L1 is transmitted. The contact state between 552 and the measuring object S is detected.

  Here, the detection of the position of the outer periphery of the optical probe at the position where the measurement light L1 is transmitted and the detection of the contact state between the sheath 552 and the measurement target S are performed as follows.

[Detection of the outer periphery of the optical probe]
First, information on the relationship between the frequency component and the intensity obtained by subjecting the interference signal for an arbitrary line to the FFT is further processed to obtain information on the relationship between the depth direction and the intensity.

  FIG. 6 is a graph illustrating a schematic example of a calculation result obtained by performing FFT on an interference signal. In FIG. 6, the horizontal axis is the depth direction and the vertical axis is the strength.

  As shown in the figure, the portion where the intensity is high and the position where the intensity peak is detected are the positions where the physical properties have changed. Therefore, this position is a boundary position between air and a substance, or a substance and another characteristic substance.

  The definition of the peak is not particularly limited, and can be set to various settings such as when the intensity becomes a certain value or more, or when the intensity change amount becomes more than a certain value.

  Here, since the substance that reflects the measurement light L1 emitted from the half ball lens 562 at the closest position is the sheath 552, the peak detected at the first peak position, that is, the position closest to the half ball lens 562 is detected. (In FIG. 6, peak P1) is the position of the outer periphery of the optical probe.

  Since the half ball lens 562 and the sheath 552 are arranged concentrically around the rotation center, the rotation center of the half ball lens 562 and the position of the outer periphery of the optical probe are a constant distance regardless of the measurement position. Therefore, the position of the outer circumference of the optical probe detected by one line can be set as the position of the outer circumference of the optical probe.

  As described above, the position of the outer periphery of the optical probe is detected.

[Detection of contact state]
First, similarly to the detection of the position of the outer periphery of the optical probe, the interference signal for one line is subjected to FFT to acquire information in the depth direction. As the detection result, a plurality of peaks are detected in the depth direction, as in the graph shown in FIG. Among the plurality of detected peaks, the first peak (peak P1 in FIG. 6) is the peak where the sheath is detected, and the peak closest to the peak where the sheath is detected (peak P2 in FIG. 6). Is the surface to be measured. That is, the position of the peak at the position closest to the center of rotation (the second shallowest position) is the position of the surface of the measuring object S.

  Next, the distance between the detected surface of the measuring object S and the outer periphery of the optical probe is detected. If the detected distance is equal to or smaller than the threshold value, it is determined that the measuring object S and the outer periphery of the optical probe are in contact. On the other hand, when the detected distance is larger than the threshold value, it is determined that the measurement object S and the outer periphery of the optical probe are in a non-contact state.

  As described above, the contact state between the sheath 552 and the measurement object S at the position where the measurement light L1 is transmitted is detected.

  Such detection is performed for each line, and the contact state between the measuring object S and the outer periphery of the optical probe is detected all around the measurement region.

[Detection of contact area]
The detection of the contact area is performed based on the detection result of the contact state of the entire circumference of the optical probe detected as described above. That is, an area that is determined to be in contact between the measurement target S and the outer periphery of the optical probe is detected as a contact area.

  FIGS. 7A and 7B are explanatory diagrams for explaining a method of detecting a contact area. A circle C1 shown in FIGS. 7A and 7B is a circle indicating the outer periphery of the optical probe.

  As shown in FIG. 2A, the surfaces S1 and S2 of the measuring object S are detected by detecting the peaks around the entire circumference. Here, the surface S <b> 1 has a portion where the sheath 552 and the measurement target S are in contact with each other, and other regions including the surface S <b> 2 are located away from the sheath 552. In such a case, the contact area detection unit 484 detects, as a contact area, an area D1 within a certain range centered on the contacting portion of the surface S1, as shown in FIG.

  The contact area detection unit 484 outputs information of the contact area detected as described above to the optical tomographic image generation unit 486 and the pressing force estimation unit 490.

[Optical tomographic image generator]
The optical tomographic image generation unit 486 generates an optical tomographic image in the depth direction by processing the interference signal converted into a digital signal by the A / D conversion unit 482.

  Here, the generation of the optical tomographic image will be briefly described. Details of this point are described in “Mitsuo Takeda,“ Optical Frequency Scanning Spectrum Interference Microscope ”, Optical Technology Contact, 2003, Vol41, No7, p426-p432”.

  When the measurement light L1 is irradiated onto the measurement object S, interference fringes with respect to each optical path length difference l when the reflected light L3 from the depth of the measurement object S and the reference light L2 interfere with each other with various optical path length differences. S (l) is the light intensity I (k) of the interference signal detected by the interference light detection unit 420. I (k) = ∫0∞S (l) [1 + cos (kl)] dl It is represented by Here, k is the wave number, and l is the optical path length difference. It can be considered that the above equation is given as an interferogram in the optical frequency domain with the wave number k = ω / c as a variable. For this reason, the optical tomographic image generation unit 486 performs fast Fourier transform on the spectral interference fringes detected by the interference light detection unit 420 and determines the light intensity S (l) of the interference light L4, thereby measuring the measurement target S. It is possible to acquire distance information from the start position and reflection intensity information and generate an optical tomographic image.

  Note that the optical tomographic image generation unit 486 generates an optical tomographic image by processing only the interference signal of the contact area based on the information on the contact area output from the contact area detection unit 484. As a result, the processing speed can be increased.

[Correction section]
The correction unit 488 performs logarithmic conversion and radial conversion on the optical tomographic image generated by the optical tomographic image generation unit 486, arranges the optical tomographic images in the order of line numbers, and forms a circular image centered on the rotation center of the optical lens. Further, the image quality is corrected by applying sharpening processing, smoothing processing, or the like to the optical tomographic image.

  The image data of the optical tomographic image subjected to the image quality correction by the correction unit 488 is output to the endoscope processor 200.

  Here, the transmission timing of the optical tomographic image is not particularly limited, and may be transmitted to the display unit every time processing of one line is finished, and may be rewritten and displayed for each line. May be transmitted at the stage where the processing of the image acquired by making one round is completed and one circular optical tomographic image is formed.

  The endoscope processor 200 converts the image data of the optical tomographic image obtained from the correction unit 488 into a signal format that can be displayed on the monitor device 16, and outputs the signal format to the monitor device 16. Thereby, the optical tomographic image is displayed on the monitor device 16.

[Pressing force estimation unit]
The pressing force estimation unit 490 estimates the pressing force of the optical probe 500 against the measurement target S based on the contact area information output from the contact area detection unit 484.

  That is, if the pressing force of the optical probe 500 against the measurement target S is changed, the contact area also changes accordingly. Therefore, the pressing force of the optical probe 500 is estimated from the size of the contact area of the optical probe 500 against the measurement target S.

  Specifically, the size of the contact range (for example, the angle formed between the center of the sheath 552 and the contact region) is obtained based on the information on the contact region, and whether or not the obtained contact range is within a preset appropriate range. Whether or not the pressing force is appropriate is determined. Here, if the obtained contact range is within an appropriate range set in advance, it is determined (estimated) as an appropriate pressing force. On the other hand, if the contact range is below the lower limit value of the appropriate range, it is determined (estimated) that pressing is insufficient, and if it exceeds the upper limit value of the appropriate range, it is determined (estimated) that pressing is excessive.

  Thus, the suitability of the pressing force of the optical probe is determined (estimated) from the size of the contact area, and the determination result is output to the endoscope processor 200.

  The endoscope processor 200 generates display data to be displayed on the monitor device 16 based on the obtained determination result, and outputs the display data to the monitor device 16.

  In addition, the display format here is not specifically limited, What is necessary is just a form which understands the appropriateness of the pressing force of an optical probe. For example, display as appropriate, deficient or excessive.

  In addition, the appropriate ranges (upper limit value, lower limit value) are obtained and set in advance by experiments or the like, and are stored in a memory (not shown) provided in the pressing force estimation unit 490, for example.

  The configuration of the diagnostic imaging apparatus 10 including the optical tomographic imaging apparatus 14 is as described above.

≪Operation of diagnostic imaging equipment≫
Next, the operation of the diagnostic imaging apparatus 10 including the optical tomographic imaging apparatus 14 will be described.

  FIG. 8 is a diagram illustrating a state in which an optical tomographic image is acquired using an optical probe.

  The optical probe 500 is inserted into the body cavity of the subject using the forceps channel of the endoscope 100. That is, the probe insertion portion 502 is inserted into the forceps insertion port 138 provided in the hand operation portion 112 of the endoscope 100, and the tip of the probe insertion portion 502 is connected to the forceps port provided in the distal end portion 144 of the endoscope 100. It protrudes from 156 and is inserted into the body cavity.

  The measurement is performed by pressing the tip of the probe insertion portion 502 of the optical probe 500 protruding from the forceps port 156 against the measurement target S (the sheath 552 is pressed against the measurement target S).

  First, a method for acquiring interference light and interference signals obtained by measuring the measurement object S will be described.

  First, the optical path length is adjusted and set so that the measuring object S is positioned in the measurable region by moving the base 470 in the arrow A direction by the mirror driving mechanism 472. Thereafter, the laser light La is emitted from the light source unit 412. The emitted laser light La is divided into the measurement light L1 and the reference light L2 by the branching / combining unit 414.

  The measurement light L1 is guided through the optical fiber FB2 and the optical probe 500, and is irradiated onto the measurement object S. Then, the light reflected at each depth position of the measuring object S enters the optical probe 500 as reflected light L3. The reflected light L3 is incident on the branching / combining unit 414 via the optical probe 500 and the optical fiber FB2.

  On the other hand, the reference light L2 enters the optical path length adjustment unit 418 through the optical fiber FB3. Then, the reference light L <b> 2 whose optical path length is adjusted by the optical path length adjusting unit 418 is guided again through the optical fiber FB <b> 3 and is incident on the branching / combining unit 414.

  The reference light L2 incident on the branching / combining unit 414 is combined with the reflected light L3 from the measurement target S, and interference light is generated. The interference light is branched into interference light L4 and interference light L5, is input to the interference light detection unit 420, and is detected as an interference signal.

  The interference signal is detected as described above. Next, an interference signal processing method will be described.

  First, a method for detecting the position of the outer periphery of the optical probe based on the interference signal will be described.

  FIG. 9 is a flowchart showing a procedure for detecting the position of the outer periphery of the optical probe based on the interference signal.

  First, an interference signal for an arbitrary line is acquired (step S10). Specifically, the interference light detection unit 420 detects the interference light generated by combining the reference light L2 and the reflected light L3 by the method described above as an interference signal.

  Next, the interference signal output from the interference light detection unit 420 as an analog signal is converted into a digital signal by the A / D conversion unit 482 (step S12).

  Next, the peak position is detected by performing FFT on the A / D converted interference signal to obtain information on the relationship between the frequency component and the intensity, and further processing to obtain the relationship between the depth direction and the intensity. (Step S14). Here, as described above, the peak position is a position where light is reflected, and is basically a boundary surface of the substance. The position of the outer periphery of the optical probe is detected from the detected peak position (step S16). Specifically, the peak detected at the position closest to the half ball lens 562 among the peak positions is detected as the position of the outer periphery of the optical probe. In this way, the position of the outer periphery of the optical probe is detected.

  Next, a method for detecting a contact area between the sheath 552 and the measurement target S will be described.

  FIG. 10 is a flowchart illustrating a procedure for detecting a contact area between the sheath and the measurement target.

  First, the line number n is set to n = 1 (step S20). Here, the line number is a number given in the order of the measurement position of the interference signal with reference to an arbitrary line. In this embodiment, since the interference signal is detected 1024 times during one rotation of the half ball lens 562, lines numbered from 1 to 1024 are arranged at equal intervals (see FIG. 5).

  Next, an interference signal of line number n is acquired (step S22). Specifically, the interference light detection unit 420 detects the interference light generated by combining the reference light L2 and the reflected light L3 by the method described above as an interference signal. Here, the line number can be determined by the position information associated with the interference signal by the interference signal acquisition unit 480.

  If the line number of the acquired interference signal is not n, the acquisition of the interference signal is repeated until the interference signal of line number n is detected.

  Next, the interference signal output from the interference light detection unit 420 as an analog signal is converted into a digital signal by the A / D conversion unit 482 (step S24).

  Next, the A / D converted interference signal is subjected to FFT to detect the peak position (step S26). Here, as described above, the peak position is a position where light is reflected, and is basically a boundary surface of the substance.

  Next, the position of the surface of the measuring object S is detected from the detected peak position (step S28). Here, no other object is basically interposed between the measuring object S and the optical probe 500. Accordingly, the peak of the position closest to the position where the sheath detected in step S16 is detected, that is, the position of the peak closest to the rotation center (the second shallowest position) is used as the surface position of the measuring object S. To detect.

  Next, a distance between the detected surface of the measuring object S and the outer periphery of the optical probe is detected, and it is determined whether the detected distance is equal to or less than a threshold value X (S30).

  Here, when the detected distance is equal to or less than the threshold value X, it is determined that the measurement object S and the outer periphery of the optical probe are in contact (step S32), and the process proceeds to step S36.

  On the other hand, when the detected distance is larger than the threshold value X, it is determined that the measurement object S and the outer periphery of the optical probe are not in contact with each other (step S34), and the process proceeds to step S36.

  Next, it is determined whether the line number n is N (step S36). Here, N is the total number of lines (that is, the number of all lines), and N = 1024 in the present embodiment.

  When the line number n is not N, n = n + 1 is set (step S38), and the process proceeds to step S22. After n is increased by 1, the process proceeds to step S22 to determine whether or not the outer periphery of the optical probe of the next line number is in contact with the measurement target.

  On the other hand, if the line number n is N, the contact determination for each line ends, and a contact range table is created (step S40).

  Here, the contact range table detects a region within a predetermined range centered on the region determined to be in contact. For example, when it is determined that the line numbers (a + 10) to (b-30) are in contact, the line number a to the line number b is set as the contact area. Note that the setting method of the contact range table is determined based on setting conditions input in advance.

  In this way, the contact range table is created, and the contact area detection process is completed.

  The contact area between the outer periphery of the optical probe and the measurement object is detected as described above.

  Next, an image processing method for creating an optical tomographic image will be described.

  FIG. 11 is a flowchart showing a procedure of image processing for creating an optical tomographic image.

  First, an interference signal of line number n that is an arbitrary line number is acquired (step S50). Specifically, the interference light detection unit 420 detects the interference light generated by combining the reference light L2 and the reflected light L3 by the method described above as an interference signal.

  Next, the interference signal output from the interference light detection unit 420 as an analog signal is A / D converted (step S52).

  Next, whether the line number n is included in the contact range table created in step S40, that is, whether it is included between the line number a and the line number b that is the contact area (whether a ≦ n ≦ b). (No) is determined (step S54).

  Here, when the line number n satisfies a ≦ n ≦ b, the A / D converted interference signal is subjected to FFT (step S56).

  Next, an optical tomographic image of line number n is acquired from the result of applying the FFT (step S58).

  Here, as described above, the optical tomographic image is subjected to a predetermined process based on the result of the FFT to obtain an image.

  When the optical tomographic image is acquired, the process proceeds to step S62.

  On the other hand, when the line number n does not satisfy a ≦ n ≦ b, that is, when n <a or b <n, masking processing is performed (step S60).

  Here, the masking process does not perform the process for acquiring the FFT and the optical tomographic image, and sets the image of the line number n as a black image or a fixed image.

  When the masking process ends, the process proceeds to step S62.

  Next, it is determined whether or not there is an end instruction (step S62).

  If there is no end instruction, n = n + 1 is set (step S64), and then the process proceeds to step S50. After n is increased by 1, the process proceeds to step S50, where an optical tomographic image of the next line number is acquired.

  Although illustration is omitted, when n = N + 1, n is set to 1 and the acquisition of the optical tomographic image is continued until an end instruction is given.

  If there is an end instruction, the process ends.

  As described above, the optical tomographic image of the measurement target is acquired.

  The image information and optical tomographic image of the mask-processed area acquired in this way are output to the correction unit 488 and subjected to image processing for display such as radial processing and sharpening processing. Thereafter, the signal is sent to the endoscope processor 200, subjected to necessary signal processing for output to the monitor device 16, and output to the monitor device 16.

  Next, a method for estimating the pressing force of the optical probe from the contact area with the measurement object will be described.

  FIG. 12 is a flowchart illustrating a procedure for estimating the pressing force of the optical probe based on the information on the contact area with the measurement target.

  First, information on the contact area is acquired, and the size of the contact range of the measuring object S with respect to the optical probe 500 is obtained (step S70).

  And it determines whether the magnitude | size of the calculated | required contact range is in the appropriate range set beforehand, and the pressing force of the optical probe 500 is estimated.

  Specifically, first, the size of the obtained contact range is compared with an upper limit value (threshold max) of an appropriate range set in advance, and it is determined whether or not the upper limit value is exceeded (step S72).

  Here, if it determines with the magnitude | size of a contact range exceeding the upper limit of an appropriate range, it will determine with pressing excessively (step S76).

  On the other hand, if it is determined that the size of the contact range is equal to or smaller than the upper limit value of the appropriate range, the contact range is compared with the lower limit value (threshold value min) of the appropriate range (step S73).

  As a result, when it is determined that the size of the obtained contact range is equal to or less than the lower limit value of the appropriate range, the pressing force is determined to be appropriate (step S75).

  On the other hand, if it determines with the magnitude | size of the calculated | required contact range being less than the lower limit of the appropriate range, it will determine with pressing force shortage (step S74).

  In this manner, the pressing force of the optical probe 500 against the contact target S is estimated based on the information on the contact area.

  Information on the obtained pressing force is output to the endoscope processor 200. The endoscope processor 200 generates display data to be displayed on the monitor device 16 based on the obtained pressing force information, and outputs the display data to the monitor device 16. As a result, information on the pressing force of the optical probe 500 against the contact target S is displayed on the monitor device 16.

  FIG. 13 is a diagram illustrating an example of a screen displayed on the monitor device.

  As shown in the figure, in the diagnostic imaging apparatus 10 of the present embodiment, an endoscopic image (observed image by the endoscope 100) acquired by the endoscope apparatus 12 on the screen of the monitor apparatus 16, and an optical tomography The optical tomographic image acquired by the imaging device 14 is displayed in parallel.

  Information on the pressing force of the optical probe 500 estimated by the pressing force estimation unit 490 is displayed on the monitor device 16 together with the endoscope image and the optical tomographic image. In this example, information of [insufficient], [appropriate], and [excess] is displayed as [optical probe pressing force] at the lower position of the optical tomographic image (in FIG. 13, the case of [appropriate] is displayed. Yes.)

  The surgeon can grasp the current pressing force of the optical probe 500 by checking the screen of the monitor device 16.

  The display form of the pressing force is not limited to this, and can be appropriately changed in consideration of other display contents.

  FIG. 14 is a diagram illustrating an example of another display form of the pressing force. In this example, the pressing force is displayed in a graph. In the example shown in the figure, a wedge-shaped graph is displayed at the lower position of the optical tomographic image, and a scale indicating the pressing force is displayed in the graph. In this case, when the pressing force is appropriate, a scale is displayed at the center of the graph (in the figure, the case where the pressing force is appropriate is displayed). On the other hand, when the pressing force is insufficient, a scale is displayed at the left end of the graph (end on the tapered side of the wedge), and when the pressing force is excessive, the right end of the graph (end on the wide side of the wedge) A scale is displayed at. Thus, the degree of pressing force can also be displayed in a graph, thereby improving visibility.

  Moreover, in this example, it is set as the structure displayed on the monitor apparatus 16 with an optical tomographic image, However, You may make it display on another display means. For example, it may be displayed using a dedicated display device. Further, for example, a lamp or the like may be turned on for display (for example, a lamp may be prepared for each shortage, appropriateness, and excess, and lighted according to the detection result).

  Further, the method of notifying the pressing force of the optical probe is not limited to this, and it may be displayed by voice or the like, or these may be used in combination. For example, when the pressing force is insufficient or excessive, a buzzer may be sounded to prompt a warning (particularly when excessive).

  As described above, according to the diagnostic imaging apparatus 10 of the present embodiment, it is possible to know the pressing force of the optical probe 500 against the measuring object S during the treatment, so that the optical tomographic image is always under an appropriate pressing force. Can be measured.

  Further, the optical tomographic imaging apparatus according to the present embodiment can detect the pressing force of the optical probe with an existing configuration without installing a pressure sensor or the like at the tip of the optical probe 500.

<< Other Embodiments for Estimating Pushing Force >>
<Other embodiment 1>
As described above, the information on the appropriate range of the contact area used when estimating the pressing force is obtained in advance by experiments or the like, but the area where the measurement target contacts the optical probe is measured even if the pressing force is the same. It depends on the target (organization). That is, as shown in FIG. 15, even when the optical probe 500 is pressed with the same pressing force, when the measurement target S is a hard tissue, the contact range becomes small (FIG. 15A), and the soft tissue In this case, the contact range becomes large ((b) in the figure).

  Therefore, when measurement is performed on various tissues with one optical probe 500, it is preferable to set an appropriate range for each measurement target.

  In this case, an appropriate range (lower limit value, upper limit value) is obtained by experiment or the like for each tissue to be measured, and a table in which the measurement object is associated with the appropriate range is created. The created table is stored in a memory (not shown) provided in the pressing force estimation unit 490, for example.

  An operator inputs information on a measurement object from an input device (not shown) at the time of measurement (for example, selecting and inputting a measurement object prepared in advance). The pressing force estimation unit 490 refers to the table and acquires information on an appropriate range corresponding to the input measurement object. And the estimation process of pressing force is performed based on the information of the acquired appropriate range.

  In this way, the pressing force can be estimated more accurately by setting an appropriate range for each measurement target.

  In the above example, the case where an appropriate range is set for each organization has been described as an example. However, it can be set in more detail. For example, the measurement object can be classified in consideration of the gender, age, etc. of the subject in addition to the tissue.

  Moreover, it can also classify | categorize according to the degree of the softness of a measuring object. That is, since the degree of tissue softness is known to some extent in advance, an appropriate range can be set according to the degree of tissue softness to be measured. For example, an appropriate range may be set for each stage by dividing into three stages of soft, standard, and hard.

<Other embodiment 2>
In the above embodiment, it is configured to determine whether the pressing force is appropriate, insufficient, or excessive by comparing the size of the contact range obtained from the contact area with the appropriate range, but the contact obtained from the contact area. The pressing force can be estimated in more detail from the size of the range.

  That is, as described above, the contact area changes according to the pressing force, so the contact range is divided into a plurality of sections, the corresponding pressing force is obtained in advance for each section, and the detected contact range is assigned to which section. It is determined whether it belongs, and the pressing force is estimated.

  For example, in the optical probe 500 of this example, since the sheath 552 is formed in a cylindrical shape, for example, when the optical probe 500 is divided into 10, the contact range (here, the angle formed with the center of the sheath 552) is 1: 0 ° to 36 °, 2: 36 ° to 72 °, 3: 72 ° to 108 °, 4: 108 ° to 144 °, 5: 146 ° to 180 °, 6: 180 ° to 216 °, 7: 216 ° to 252 ° 8: 252 ° to 288 °, 9: 288 ° to 324 °, 10: 324 ° to 360 °. Therefore, the pressing force is obtained for each divided section by experiments or the like (determined within a measurable range), and a table is created (a table in which the pressing force is associated with each section is created).

  The table is stored, for example, in a memory (not shown) provided in the pressing force estimation unit 490, and the pressing force is estimated with reference to this table. For example, the pressing force estimation unit 490 obtains and obtains the size of the contact range (here, the angle formed by the contact region with the center of the sheath 552) based on the contact region information obtained from the contact region detection unit 484. It is determined to which category the size of the contact range belongs. And the information of the pressing force of a corresponding division is acquired.

  Thus, by dividing the contact range into a plurality of categories and determining which category the obtained contact range belongs to, it is possible to grasp the more accurate pressing force by estimating the pressing force. .

  In this embodiment, the pressing force can be obtained in more detail. Therefore, when the pressing force is displayed in a graph on the monitor device 16 as shown in FIG. 14, the position of the scale according to the obtained pressing force. Move to display. That is, as the pressing force increases, the image moves to the right side (wide side) in the figure and is displayed. In this case, for example, it is preferable to distinguish and display the appropriate range by changing the color so that it can be visually confirmed that the large pressure is within the appropriate range.

  Further, when pressing is excessive or when pressing is insufficient, it is preferable to use a buzzer or the like to warn, for example. In this case, for example, when the pressing force is excessive, it is preferable to change the volume of the buzzer according to the magnitude of the pressing force (the sound increases as the pressing force increases).

  In addition, according to the present embodiment, the pressing force can be obtained in more detail, and therefore the possibility of bending (kinking) of the optical probe 500 formed in a catheter shape can be predicted. That is, the bending stress in the longitudinal axis direction of the optical probe 500 can be measured from the estimated pressing force, and the possibility of kinking of the optical probe 500 can be predicted from the measurement result. Thereby, it can be used more safely.

  In this example as well, when measuring a plurality of tissues, it is preferable to prepare a table for each measurement target. Thereby, the pressing force can be estimated more accurately.

<Other embodiment 3>
In the present embodiment, the pressing force is estimated based on the optical tomographic image acquired by the optical tomographic imaging apparatus 14.

  FIG. 16 is a block diagram illustrating a configuration of a processing unit of the optical tomographic imaging apparatus according to the present embodiment.

  As shown in the figure, the processing unit 422A of the optical tomographic imaging apparatus according to the present embodiment acquires the optical tomographic image after the image quality correction generated by the correcting unit 488, and estimates the pressing force. 490A is provided.

The pressing force estimation unit 490A obtains the shape of the surface of the measuring object S from the optical tomographic image acquired from the correction unit 488, and estimates the pushing force from the degree of deformation of the obtained surface shape. That is, since the surface shape of the measuring object S changes according to the pressing force of the optical probe 500, the pressing force is estimated based on the degree of deformation. Specifically, a curve that describes the surface is extracted from the acquired optical tomographic image, the degree of deformation is evaluated, and the pressing force is estimated. More specifically, to extract the surface from the optical tomographic images, a shape on its surface is approximated by a cubic curve, it calculates an integrated value of the absolute value of the differential coefficient of the cubic curve that approximates as the evaluation value. Then, it is determined whether or not the calculated evaluation value is within an appropriate range, and the pressing force is estimated. That is, the integral value of the absolute value of the differential coefficient of the curve serves as an index indicating the degree of deformation of the curve. Therefore, by obtaining this as an evaluation value, it is possible to estimate the appropriateness of the pressing force from the magnitude of the evaluation value. .

  FIG. 17 is a flowchart showing a procedure for estimating the pressing force from the optical tomographic image.

  First, an optical tomographic image is acquired from the correction unit, and the edge of the surface to be measured is extracted (step S80).

  Next, the extracted edge is approximated by a cubic curve (step S82).

  Next, an integral value of the absolute value of the derivative of the obtained cubic curve is calculated, and an evaluation value is acquired (step S84).

  Next, it is determined whether or not the acquired evaluation value exceeds an upper limit value (threshold max) of an appropriate range set in advance (step S86).

  Here, this appropriate range is obtained in advance by experiments or the like and stored in a memory (not shown) provided in the pressing force estimation unit 490A.

  As a result of this determination, if the evaluation value exceeds the upper limit value of the appropriate range, it is determined (estimated) that pressing is excessive (step S94), and the process is terminated.

  On the other hand, if it is determined that the evaluation value is equal to or lower than the upper limit value of the appropriate range, it is next determined whether the evaluation value is below a lower limit value (threshold value min) of the appropriate range set in advance (step S88).

  As a result of this determination, if it is determined that the evaluation value is greater than or equal to the lower limit value of the appropriate range, it is determined that the pressing force is appropriate (step S92), and the process ends.

  On the other hand, if the evaluation value is below the lower limit value of the appropriate range, it is determined that the pressing is insufficient (step S90), and the process ends.

  Thus, in the present embodiment, the pressing force of the optical probe 500 is estimated based on the optical tomographic image. Therefore, also in this embodiment, the pressing force of the optical probe can be detected with the existing configuration without installing a pressure sensor or the like at the tip of the optical probe 500.

  Also in this example, as in the case of the other embodiment 1, when measuring a plurality of tissues, it is preferable to set an appropriate range for each measurement target. Thereby, the pressing force can be estimated more accurately.

  Also in this example, as in the case of the other embodiment 2 described above, the evaluation value is divided into a plurality of sections, and the pressing force is estimated more accurately by obtaining and setting the pressing force for each section in advance. can do. And the possibility of the kink of the optical probe 500 can be predicted by obtaining the pressing force in more detail in this way.

<Other embodiments>
The configuration of the optical tomographic imaging apparatus to which the present invention is applied is not limited to that of the above-described embodiment. For example, the configuration of acquiring an optical tomographic image to be measured by SD-OCT (spectral domain-OCT) measurement, The present invention can be similarly applied to an optical tomographic imaging apparatus configured to acquire an optical tomographic image to be measured by TD-OCT (time domain-OCT) measurement.

  DESCRIPTION OF SYMBOLS 10 ... Image diagnostic apparatus, 12 ... Endoscope apparatus, 14 ... Optical tomographic imaging apparatus, 16 ... Monitor apparatus, 100 ... Endoscope, 112 ... Hand operation part, 114 ... Endoscope insertion part, 116 ... Universal cable , 130 ... Air / water supply button, 132 ... Angle knob, 134 ... Suction button, 136 ... Shutter button, 138 ... Forceps insertion port, 140 ... Soft part, 142 ... Curved part, 144 ... Tip part, 150 ... Observation optical system , 152 ... Illumination optical system, 154 ... Cleaning nozzle, 156 ... Forceps port, 200 ... Endoscope processor, 300 ... Light source device, 400 ... OCT processor, 412 ... Light source unit, 414 ... Branching / combining part, 416 ... Branching part DESCRIPTION OF SYMBOLS 418 ... Optical path length adjustment part 420 ... Interference light detection part 422 ... Processing part 422A ... Processing part 440 ... Semiconductor optical amplifier, 442 ... Optical branching part, 444 ... Collimator Lens, 446 ... diffraction grating element, 448 ... optical system, 450 ... rotating polygon mirror, 464 ... first optical lens, 466 ... second optical lens, 468 ... reflecting mirror, 470 ... base, 472 ... mirror drive mechanism, 480 ... interference signal acquisition unit, 482 ... A / D conversion unit, 484 ... contact area detection unit, 486 ... optical tomographic image generation unit, 488 ... correction unit, 490 ... pressing force estimation unit, 490A ... pressing force estimation unit, 500 ... Optical probe, 502 ... probe insertion portion, 504 ... drive portion, 506 ... cable, 552 ... sheath, 554 ... cap, 556 ... optical fiber, 558 ... spring, 560 ... fixed tube, 562 ... half ball lens, FB1 to FB11 ... Optical fiber, S ... measurement object, La ... laser light, L1 ... measurement light, L2 ... reference light, L3 ... reflected light, L4, L5 ... interference light

Claims (15)

A light source;
Branching means for branching light emitted from the light source into measurement light and reference light;
An optical probe comprising a measurement unit in the sheath, irradiating the measurement light from the measurement unit toward the measurement target, and acquiring the reflected light;
Driving means for rotating the measuring part of the optical probe;
A multiplexing unit configured to combine the reflected light acquired by the measurement unit of the optical probe and the reference light to generate interference light;
Interference light detecting means for detecting the interference light as an interference signal;
An optical tomographic image acquisition means for acquiring an optical tomographic image from the interference signal detected by the interference light detection means;
Contact area detecting means for detecting a contact area of the optical probe with respect to the measurement object;
A pressing force estimating means for estimating the pressing force of the optical probe against the measurement object based on the size of the contact area detected by the contact area detecting means;
Notification means for notifying the pressing force of the optical probe estimated by the pressing force estimation means;
An optical tomographic imaging apparatus comprising:   The pressing force estimation means determines whether or not the contact area detected by the contact area detection means is within an appropriate range set in advance, and estimates the pressing force of the optical probe against the measurement target. The optical tomographic imaging apparatus according to claim 1.   The optical tomographic imaging apparatus according to claim 2, wherein the appropriate range is set for each measurement target.   A storage unit storing a table representing a relationship between the contact area and the pressing force is provided, and the pressing force estimation unit estimates the pressing force of the optical probe with respect to the measurement target with reference to the table. The optical tomographic imaging apparatus according to claim 1.   The table is prepared for each measurement target and recorded in the storage unit, and the pressing force estimation unit estimates the pressing force of the optical probe with respect to the measurement target with reference to the table corresponding to the measurement target. The optical tomographic imaging apparatus according to claim 4. A light source;
Branching means for branching light emitted from the light source into measurement light and reference light;
An optical probe comprising a measurement unit in the sheath, irradiating the measurement light from the measurement unit toward the measurement target, and acquiring the reflected light;
Driving means for rotating the measuring part of the optical probe;
A multiplexing unit configured to combine the reflected light acquired by the measurement unit of the optical probe and the reference light to generate interference light;
Interference light detecting means for detecting the interference light as an interference signal;
An optical tomographic image acquisition means for acquiring an optical tomographic image from the interference signal detected by the interference light detection means;
A pressing that detects the shape of the surface of the measurement target based on the optical tomographic image acquired by the optical tomographic image acquisition unit and estimates the pressing force of the optical probe against the measurement target based on the shape of the surface Force estimation means;
Notification means for notifying the pressing force of the optical probe estimated by the pressing force estimation means;
An optical tomographic imaging apparatus comprising:   The pressing force estimation means extracts a curve that defines the surface of the measurement object, calculates an integral value of an absolute value of a differential coefficient of the curve as an evaluation value, and based on the evaluation value, the measurement for the measurement object The optical tomographic imaging apparatus according to claim 6, wherein the pressing force of the optical probe is estimated.   The said pressing force estimation means judges whether the said evaluation value is in the appropriate range set beforehand, and estimates the pressing force of the said optical probe with respect to the said measuring object, The 7th aspect is characterized by the above-mentioned. An optical tomographic imaging apparatus according to 1.   The optical tomographic imaging apparatus according to claim 8, wherein the appropriate range is set for each measurement target.   The pressing force estimation means estimates a pressing force of the optical probe against the measurement target with reference to a table representing a relationship between the pressing force of the optical probe with respect to the measurement target and the evaluation value. The optical tomographic imaging apparatus according to claim 7.   The optical tomographic imaging apparatus according to claim 10, wherein the table is prepared for each measurement target. A display means,
The notification means displays the pressing force of the optical probe estimated by the pressing force estimation means on the display means together with the optical tomographic image acquired by the optical tomographic image acquisition means, and displays the pressing force of the optical probe. The optical tomographic imaging apparatus according to claim 1, wherein the optical tomographic imaging apparatus is notified. A determination unit that determines whether or not the pressing force of the optical probe with respect to the measurement target is appropriate based on the pressing force of the optical probe estimated by the pressing force estimation unit;
Warning means for warning when the determination means determines that the pressing force of the optical probe is not appropriate;
The optical tomographic imaging apparatus according to claim 1, wherein the optical tomographic imaging apparatus is provided. A light source, branching means for branching the light emitted from the light source into measurement light and reference light, a measurement unit in the sheath, and irradiating the measurement light from the measurement unit toward the measurement object; An optical probe that acquires reflected light, a driving unit that rotates the measurement unit of the optical probe, and a reflected light acquired by the measurement unit of the optical probe and the reference light are combined to generate interference light. Optical tomographic imaging comprising wave means, interference light detection means for detecting the interference light as an interference signal, and optical tomographic image acquisition means for acquiring an optical tomographic image from the interference signal detected by the interference light detection means An optical probe pressing force estimation method for an apparatus, comprising:
An optical probe of an optical tomographic imaging apparatus that detects a contact area of the optical probe with respect to the measurement object and estimates a pressing force of the optical probe with respect to the measurement object based on a size of the contact area Pushing force estimation method. A light source, branching means for branching the light emitted from the light source into measurement light and reference light, a measurement unit in the sheath, and irradiating the measurement light from the measurement unit toward the measurement object; An optical probe that acquires reflected light, a driving unit that rotates the measurement unit of the optical probe, and a reflected light acquired by the measurement unit of the optical probe and the reference light are combined to generate interference light. Optical tomographic imaging comprising wave means, interference light detection means for detecting the interference light as an interference signal, and optical tomographic image acquisition means for acquiring an optical tomographic image from the interference signal detected by the interference light detection means An optical probe pressing force estimation method for an apparatus, comprising:
An optical tomographic imaging apparatus that detects the shape of the surface of the measurement target based on the optical tomographic image and estimates the pressing force of the optical probe against the measurement target based on the shape of the surface Method for estimating the pressing force of the optical probe.

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